What if the dialog has a mistake in it, and instead of using the variable for the character's name, it says "mom"? Do you ignore it, or drop the game?
For myself I take various factors into account.
1- how well the game is developed over all. Does the "fetish" fit or is it only there because.
Examples to me of where it fits is a game like Dark Neighborhood where the MC clearly isn't parttaking in "fetish" under his own free will.
If the MC is just blatantly knowingly perving on his family that's when I lose interest.
2- How the script is written out.
I don't hold it against a Dev if they forget to use Nurse instead of Mom every now and then.
However when they start using phrasing like "I can't believe I have these feelings, Surely I am not the only one who has them after giving birth to tenants" or when an MC says something like " wow my twin best friend is in the shower with the door open, Did she forget to close it on purpose?"
To me in those situations the Dev isn't even caring to try and might as well not even bother changing it.
3- Is the game fun to play and or are interactions with certain characters forced or optional?
The 2 reasons I can overlook the occasional reference in this game or in Sumertime Saga for example is for one I don't have to screw linda or Sarah if I don't want to Just like in STS I can ignore Debi Or Jenny if I want to. Plus in both I have options to go where I want and interact with who I want. And that makes the "fetish" like 3% more tolerable. Granted the story doesn't progress in those cases but meh..
That's basically my opinion on that.
